Johnny Cash, akathe Man in Black, was the king of infinite cool, and not exactly someone who would automatically come to mind when you think of lullabies or music with which to soothe babies. That is until the proud parents of 9-month-old twins Reece and Levi decided to use Cash as the soundtrack while their twins bounce around in their Jolly Jumpers.

Reece and Levi are popping up and down in their super fun exercise toy -- don't those things look like hours and hours of endless entertainment? -- as Cash's music rumbles low in the background in this YouTube video. They are enjoying themselves, giggling and gurgling without a care in the world. In fact, they can bounce around all day, poop in their diapers and not even blink or think twice. They're infants with little concern for such matters. They just want to jump.

Cash's music obviously enhances the pair's Jolly Jumper experience, but something tells us their parental units could blast death metal or a boy band and the kids would enjoy their jumping just the same.

The usage of Johnny Cash as the background music proves how cool Reese and Levi's parents are, too. At least Mom and Dad are starting them early on quality music. For that, we applaud them and their parenting skills.

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